ChainSwap July 2, 2021 exploit
An attacker exploited the ChainSwap bridge and withdrew assets from wallets that had interacted with it. The team froze the bridge and nodes, deployed a fix, and estimated total damage at approximately $800,000.
Incident facts
- Incident title
- ChainSwap July 2, 2021 exploit
- Bridge
- ChainSwap
- Incident date
- 2021-07-02
- Incident type
- Exploit
- Major incident
- Yes
- Affected chains
- Ethereum, BNB Chain, Unknown
- Affected assets
- Unknown
- Attack category
- Cross Chain Contract Exploit
- Reported loss
- Approximately $800,000
- Amount confidence
- High
- Loss amount basis
- Official ChainSwap Post Mortem
- Recovery
- Partial Recovery
- Reimbursement
- In Progress
- Restart
- Reopened
- Current outcome
- Active After Incident
- Postmortem
- Full
- Resolution
- Unresolved
- Last reviewed
- 2026-07-28
- Last verified
- 2026-07-28
Amount and valuation
ChainSwap's official post-mortem estimated total damage at around $800,000.
The amount is an official estimate rather than an independently reconciled total.
total damageapproximately $800,000
Canonical incident estimate.
Why this remains unresolved
- The official post-mortem said full compensation was almost complete, but final completion is not established in this batch.
Timeline events
ChainSwap froze the bridge after the first July exploit2021-07-02
ChainSwap reported freezing the bridge and shutting down nodes after detecting anomalous withdrawals, with a fix deployed shortly afterward.
ChainSwap announced treasury-funded compensation2021-07-04
The team said affected users would be compensated from the ChainSwap treasury and described full compensation as almost complete.
Final completion is not independently established.
ChainSwap bridge relaunched after the July incident period2021-08-20
ChainSwap announced that its bridge was live again after integrating with Anyswap and completing the post-July remediation period.
This records the later final relaunch after the combined July remediation period; it does not claim a durable reopening before the second exploit.
Evidence records
- ChainSwap post-mortem and compensation planChainSwap · Tier 1 · High reliability · primary · 2021-07-04Claim scope: Incident Case
Primary post-mortem for the July 2 exploit and compensation plan.
- ChainSwap re-launch, we are liveChainSwap · Tier 1 · High reliability · primary · 2021-08-20Claim scope: Restart
Duplicate official relaunch URL retained as separate event-scoped evidence for the first July incident.
- ChainSwap post-mortem and compensation planChainSwap · Tier 1 · High reliability · primary · 2021-07-04Claim scope: Reimbursement
Event-scoped duplicate of bir_src_000071: ChainSwap's official July 2 postmortem announces treasury-funded compensation and describes progress.
Source tiers describe evidence authority, not certainty for every claim. Tier 1 is the strongest source class; Tier 2 and Tier 3 provide progressively more secondary or supporting context. Source notes define what each record actually supports.
Known unknowns
- The final compensated amount and completion date remain unverified.
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Report a correction
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